Differential phase contrast and dark-field imaging (DPCI and DFI) are promising technologies that will likely add additional diagnostic value e.g. for mammography or for pre-clinical application with small animals, in addition to attenuation imaging. A conventional X-ray source can be used with a Talbot-Lau interferometer and a conventional X-ray detector. However, in a class of tasks where DPCI and DFI is not required, the interferometer is moved out of the beamline. This is cumbersome, and can lead to misalignment issues when the interferometer is moved back again when DPCI and DFI are again required.
US2007/0183559A1 discloses an X-ray CT system is for producing tomographic phase contrast and absorption images wherein the gratings for phase contrast are displaced accordingly.